Folding structure

ABSTRACT

The invention relates to a folding structure provided with a lock structure for the folding leg stud, which is capable of releasing the respective locked state by pressing the lock lever being in almost the same standby position even when the leg stud is deployed or folded.  
     In this folding structure, even when the lock device as described above is used, the leg stud is allowed for compact storage without taking much space and thus a highly reliable folding structure can be provided.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a folding structure having a lock device for locking a leg stud foldably mounted on a basal plate such as a top board or a seat board in a deployed position and a folded position respectively.

[0003] 2. Description of the Related Art

[0004] In the related art, as a folding structure such as a desk in which a foldable leg stud is locked, a lock device disclosed in Japanese Examined Utility Model Publication No.61-32507 is known. In this structure, since the leg stud is locked when it is in the deployed state but not in the folded state, there arise problems such that it may unexpectedly move in the deploying direction when the folded leg stud is lifted up for transportation.

[0005] Therefore, it is desired that the leg stud be locked not only in the deployed state, but also in the folded state.

[0006] Since the locking positions of the leg stud between the deployed state and the folded state are away from each other by the extent corresponding to the rotational angle of the leg stud, a locking structure including separate locking members is conceivable. However, there is a drawback that the structure is increased in size and in complexity.

[0007] Therefore, deployment of a lock device in which locking and unlocking operations of the leg stud can be performed by means of an identical lock lever both in the deployed position and a the folded position analogously has been expected.

[0008] On the other hand, in the folding structure provided with this type of lock device, since the leg stud is folded over the lock device, the height in the folded state increases correspondingly.

[0009] Therefore, there are recognized problems in that an extra space for storage is required and in that they take up much space when it is stacked one on another.

SUMMARY OF THE INVENTION

[0010] With such problems in view, it is a first subject of the invention to provide a reliable locking structure of the folding leg stud in which the respective locked states may be released by pressing a lock lever in the standby position toward the basal board both for deploying and folding the leg stud.

[0011] It is a second subject of the invention to provide a locking structure of the folding leg stud provided with a stopper on a supporting bracket for rotatably attaching the leg stud for limiting the deployed position and the folded position of the leg stud so that the overall structure is simplified and thus the costs are saved.

[0012] With the drawbacks described above in view, it is a third subject of the invention mainly to provide a novel folding structure in which the leg stud can be folded without taking much space even with the lock device as described above.

[0013] It is a fourth subject of the invention to provide a reliable folding structure that allows for compact storage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is an exploded perspective view of a lock device in accordance with a first embodiment of the invention in the mounted state;

[0015]FIG. 2 is a perspective view showing a table in accordance with the first embodiment;

[0016]FIG. 3 is a perspective view of the lock device showing a state in which the leg stud is in the folded position;

[0017]FIG. 4 is a side view of the same;

[0018]FIG. 5 is a perspective view of the lock device showing a state in which the leg stud is in the deployed position;

[0019]FIG. 6 is a side view of the same;

[0020]FIG. 7A is a partial side view of the lock device showing a state in which the leg stud is in the deployed position;

[0021]FIG. 7B is a partial side view of the lock device showing a state in which the leg stud is in the folded position;

[0022]FIG. 8 is an exploded perspective view showing the mounted state of the lock device for a table in accordance with a second embodiment;

[0023]FIG. 9 is a side view of the lock device in a state in which the leg stud is in the folded position;

[0024]FIG. 10 is a perspective view of a table in accordance with a third embodiment of the invention;

[0025]FIG. 11 is a front view of the leg stud in a folded position;

[0026]FIG. 12 is a perspective view of a table in accordance with the fourth embodiment;

[0027]FIG. 13 is a front view of the same;

[0028]FIG. 14 is an exploded perspective view of a principal portion of the third embodiment;

[0029]FIG. 15 is a perspective view of the principal portion in a state in which the leg stud is in the deployed position;

[0030]FIG. 16 is a perspective view of the principal portion in a state in which the leg stud is in the folded position;

[0031]FIG. 17 is a side view of the principal portion in a state in which the leg stud is in the deployed position;

[0032]FIG. 18 is a side view of the principal portion in a state in which the leg stud is on route between the folded position and the deployed position;

[0033]FIG. 19 is a side view of the principal portion in a state in which the leg stud is in the folded position;

[0034]FIG. 20A is a partial side view showing the locking state of the lock device in a state in which the leg stud is in the deployed position;

[0035]FIG. 20B is a partial side view showing the locking state of the lock device in a state in which the leg stud is in the folded position;

[0036]FIG. 21 is a partial perspective view showing a leg stud in accordance with another embodiment;

[0037]FIG. 22 is a perspective view of the lock device showing a state in which the leg stud is in the deployed position in accordance with a fifth embodiment;

[0038]FIG. 23 is a perspective view of the lock device showing a state in which the leg stud is in the folding position in accordance with a fifth embodiment; and

[0039]FIG. 24 is a side view of the lock device showing a state in which the leg stud is in the deployed position in accordance with a fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Referring now to the drawings, an embodiment in which a folding structure is applied to a table will be described.

[0041] A table T1 in the first embodiment shown in FIG. 2 comprises a top board A, a pair of leg studs 5 mounted on the top board A so as to be rotatable between the deployed position and the folded position, and a lock device 1 for locking the leg stud 5 in the deployed position and in the folded position.

[0042] In the figure, the reference sign C designates a proximal cap of the leg stud, D designates a height adjustment screw of the leg stud, E designates a caster, F designates a side end cap of the leg stud, and G designates a horizontal adjustment screw.

[0043] The leg stud 5 in the figure comprises a supporting leg portion 5 a and a leg base portion 5 b extending in the fore-and-aft direction at the lower end thereof.

[0044] The leg stud 5 is rotatably attached to the supporting bracket 2 fixed on the backside of the top board A with a first pin P1 via a cam bracket 3 of the lock device 1 provided at the upper end of the supporting leg portion 5 a so as to be rotatable between the deployed position and the folded position.

[0045] The lock device 1 comprises, as shown in FIG. 1 through FIG. 6, the supporting bracket 2 including a lock lever 4 rotatably attached thereto with a second pin P2 and the cam bracket 3 to be rotatably attached to the supporting bracket 2 with the first pin P1 in combination.

[0046] In other words, the supporting bracket 2 comprises a basal plate portion 20 integrally therewith, and is secured integrally on the backside of the top board A with a tap screw 12.

[0047] The supporting bracket 2 includes a side plate 2 a, whereof the end on the leg stud side forms a deployment stopper 21 defining a prescribed angle (angle of deployment of the leg stud; 90 degrees in the example shown in the figure) with respect to the top board A.

[0048] Therefore, the angle of deployment of the leg stud 5 may be determined to a desired angle by adjusting the angle of that end, that is, the deployment stopper 21, with respect to the top board A.

[0049] The lower edge of the side plate 2 a of the supporting bracket 2 is provided with a recess serving as a lock pin stopper 22, which will be described later, and a fold stopper 23 formed at the lowest edge thereof for supporting the leg stud 5 (the supporting leg portion 5 a in this embodiment) in a folded position.

[0050] The lock lever 4 is rotatably attached to the side plate 2 a of the supporting bracket 2 with the second pin P2 in the position away from the position in which the first pin P1 is passed through, so that it is capable of tilting.

[0051] A coil spring 8 is routed between the lock lever 4 and the supporting bracket 2 via the hooks 9 fixedly provided thereon respectively for urging the lock lever 4 in the locking direction (the direction in which a lock pin 7 moves toward the top board A).

[0052] The lock lever 4 has a pair of left and right side plates 4 a each formed with a hole for passing the second pin P2 at the midway thereof, and is provided with the lock pin 7 that serves as a locking portion fixedly at the front end, and a lever handle 41 that serves as an operating strip molded at the rear end integrally therewith with a bent portion interposed therebetween.

[0053] The lever handle 41 may be covered with resin or rubber to improve a tactile impression.

[0054] The cam bracket 3 fixed on the leg stud 5 has a channel shape in cross section, and the left and right side plates 3 a thereof serve as locking cam strips 30. The bottom of the channel extends outward to form a fold receiving surface 36 for receiving the fold stopper 23, which will be described late, when it is brought into contact therewith.

[0055] The locking cam strip 30 comprises a deployment lock receiving portion 32 and a fold lock receiving portion 35, and a trace cam 34 formed between the receiving portions 32, 35, so that the lock pin 7 of the lock lever 4 is always kept in contact therewith by the urging force.

[0056] The locking cam strip 30 is formed with the fold lock receiving portion 35 in the position where the lock pin 7 engages so that the lever handle 41 is disposed between the folded supporting leg portion 5 a and the top board A in the standby position, that is, in almost parallel therewith, when the leg stud 5 is folded (See FIG. 3, FIG. 4).

[0057] In the case of the example shown in the figure, the locking cam strip 30 is formed with a notch to form a passage section 33 on the proximal side along the supporting leg portion 5 a in such a manner that the lock pin 7 is fitted into the space between the locking cam strip 30 and the supporting leg portion 5 a when the leg stud 5 is folded, and is formed with the fold lock receiving portion 35 recessed in the passage section 33 in the position orthogonal thereto.

[0058] The fold lock receiving portion 35 is adapted to be in alignment with the lock pin stopper 22 in a position in which the leg stud is folded as shown in FIG. 3 and FIG. 4.

[0059] The opened side of the passage section 33 continuing into the fold lock receiving portion 35 projects as a lock claw portion 31 and constrains the lock pin 7 even when a force of the leg stud 5 in the deploying direction is exerted thereon.

[0060] The locking cam strip 30 is formed with a deployment lock receiving portion 32 in the position away from the fold lock receiving portion 35 to the extent corresponding to the angle between the deployed position and the folded position of the leg stud 5 about a fulcrum to which the leg stud 5 is rotatably attached (P1).

[0061] When the leg stud 5 is deployed as shown in FIG. 5 and FIG. 6, the lock pin 7 engages the deployment lock receiving portion 32, and in that position, the lever handle 41 takes almost the same position as the standby position that is taken when the leg stud 5 is folded.

[0062] In such arrangement, when the leg stud 5 is deployed, the supporting leg portion 5 a is brought into contact with the deployment stopper 21 of the supporting bracket 2, which defines a locking surface R1, for preventing further rotation as shown in FIG. 7A, and the lock pin 7 of the lock lever 4 engages the deployment lock receiving portion 32 that forms a deployment locking point R2 for locking the leg stud 5 in the deployed position.

[0063] At this moment, the lever handle 41 takes the standby position away from the backside of the top board A in substantially parallel therewith as shown in FIG. 5 and FIG. 6.

[0064] When the lever handle 41 is pressed toward the top board (the direction a in the figure) and the lock lever 4 is rotated about the second pin P2, the lock pin 7 comes out from the deployment lock receiving portion 32 and thus is released therefrom. Then the leg stud 5 is rotated in the folding direction (the direction b) about the first pin P1, and is displaced to the locking surface R5 on which the leg stud 5 is brought into contact with the fold stopper 23 (See FIG. 6, FIG. 7B).

[0065] In order to rotate the leg stud 5 in the folding direction, by moving the hand away from the lever handle 41, the lock pin 7 is tilted against the trace cam 34 formed on the edge of the locking cam strip 30 by a urging force, and in the folding position shown in FIG. 4, it is moved from the passage section 33 over the deployment lock claw portion 31 and then is automatically fitted into and engaged with the fold lock receiving portion 35, and thus is constrained by the fold locking point R3 and the bottom dead center of the lock lever R4, so that the reverse rotation of the leg stud 5 in the deploying direction (the direction c) is constrained (See FIG. 7b).

[0066] In this embodiment, the first pin P1 is set slightly below the second pin P2, and the locking points R2, R3 between the lock pin 7 and the respective receiving portions 32, 35 are positioned lower (higher in FIG. 7) than a line segment between the P1 and P2 so as to constrain the reverse rotation of the leg stud 5.

[0067] As described above, the lever handle 41 is disposed between the leg stud 5 and the top board A in almost parallel therewith when the leg stud 5 is folded, and moves back to the position almost the same as the standby position which is taken when the leg stud 5 is deployed (See FIG. 3, FIG. 4).

[0068] In order to deploy the leg stud 5 again from the folded position, the lever handle 41 is pressed toward the top board A in the direction a analogously, the leg stud 5 is tilted in the deploying direction about the first pin P1 while tilting the lock lever 4 about the second pin P2, then the lock pin 7 is freed from the fold lock receiving portion 35 and is allowed to move over the lock claw portion 31 and get out from the passage section 33.

[0069] Since the lock pin 7 gives a force to the leg stud 5 in the deploying direction within the range of its rotational trajectory when the leg stud 5 is kept in a stationary state, the leg stud 5 is urged in the deploying direction and thus it can easily be deployed.

[0070] Subsequently, the leg stud 5 is gripped and rotated in the deploying direction (direction c), and is displaced to the position where it comes into contact with the deployment stopper 21 shown in FIG. 6.

[0071] In this case, the locking pin 7 that is not subjected to a pressing force now is brought into contact with and moved along the trace cam 34 of the locking cam strip 30 by a resilient force, and then is automatically fitted into the deployment lock receiving portion 32 in the position where the leg stud 5 is brought into contact with the deployment stopper 21.

[0072] As described above, the standby position of the lever handle 41 at this moment is almost the same position as the standby position that is taken when the leg stud 5 is folded.

[0073] In this embodiment, an angle formed by the deployment stopper 21 defined by the edge of the side plate 3 a of the supporting bracket 3 and the top board A is the angle at which the leg stud 5 is held. Therefore, the angle of the leg stud 5 when being deployed is not limited to perpendicular, but it may be set to a desired angle, such as tapered legs that are broaden toward the floor.

[0074] Likewise, the angle formed between the leg stud 5 and the top board A in the folded position is determined by the distance from the top board (height) of the fold stopper 23. Therefore, the leg stud 5 in the folded state is not necessarily in parallel with the top board A as the example shown in the figure, but the folded position may be set at any desired angle by varying the height of the fold stopper 23.

[0075] Since this embodiment comprises the supporting bracket 2 having the lock lever 4 rotatably attached thereon and the cam bracket 3 as described above, it may be mounted freely irrespective of the types or the configurations of the leg stud 5.

[0076] In other words, while the case where the leg stud 5 is T-shape in plan view is shown in the embodiment, it may be any other configuration.

[0077] For example, as a table T2 in the second embodiment shown in FIG. 8 and FIG. 9, when the leg stud 5 is U-shape in plan view or inverted angular U and comprises a pair of supporting legs 5 a′ and an upper horizontal member 5 c connecting the upper ends thereof, the supporting bracket 2 of the lock device 1 and the cam bracket 3 are increased in width and set to have a height not more than the height of the upper horizontal member 5 a.

[0078] The fold stopper 23 is disposed between the deployment stopper 21 and the lock pin stopper 22, so as to be able to come into contact with the fold receiving surface 36 of the upper horizontal member 5 a in the folded state.

[0079] The spring 8 is fitted on the second pin P2, and engaged with the lock lever 4 at one end and with the bottom of the channel of the supporting bracket 2 at the other end, so as to urge the lock lever 4 in the locking direction.

[0080] Since other constructions are the same as those of the lock device 1 of the table T1 described in the first embodiment, the identical parts are designated by the identical numerals and will not be described again.

[0081] A table T3 in the third embodiment shown in FIG. 10 and FIG. 11 comprises the top board A, the leg stud 5 rotatably attached to the top board A so as to be capable of being deployed and folded freely, and a lock device 1 for locking the leg stud 5 in the deployed position and in the folded position.

[0082] The leg stud 5 of this embodiment is substantially inverted U-shape comprising a pair of supporting leg portions 51, and a horizontal member 52 connecting the upper ends of the supporting leg portions 51.

[0083] The leg stud 5 is rotatably attached to the supporting bracket 2 fixed on the backside of the top board A with the first pin P1 via the cam bracket 3 of the lock device 1 provided at the center of the horizontal member 52 so as to be rotatably between the deployed position and the folded position.

[0084] The horizontal member 52 has a center portion 52 a formed into the horizontal surface, and both of the left and right ends 52 b incline gradually inwardly or toward the inside of the leg studs in the deployed position, that is, toward the top board A when the leg stud is folded.

[0085] In the example shown in the figure, as is clear from FIG. 14, the horizontal member 52 is provided with a cylindrical portion 53 integrally attached to the end thereof, a leg stud body 54 is fitted into the cylindrical portion 53 from above in the figure, and a protective cap 55 formed of synthetic resin or rubber is engaged from the lower side of the figure, so that both of them are secured to form the supporting leg portion 51.

[0086] Though the protective cap 55 and the leg stud body 54 are fixed together with a screw to form a single unit in the example shown in the figure, the way to fix them together as a single unit is not specifically limited and the leg stud body 54 may be fixed directly to the cylindrical portion 53.

[0087] In such an arrangement, as shown in FIG. 11, the horizontal member 52 of the leg stud 5 is positioned away from the backside of the top board A due to the existence of the lock device 1 when the leg stud 5 is folded.

[0088] On the other hand, since the supporting leg portion 51 is positioned close to the top board A due to the inclination of the horizontal member on both ends, it never project over the horizontal member 52.

[0089]FIG. 21 shows a supporting leg portion 51′ according to another embodiment.

[0090] In this case, a plate bracket 56 is integrally attached to the end of the horizontal member 52, and the bracket 56 is formed with a screw hole.

[0091] On the other hand, a leg stud body 54′ is formed of a wooden column, and formed with a recess 54 a′ on the upper inner side. The bottom wall of the recess 54 a′ is formed with a pair of upper and lower holes.

[0092] The bracket 56 is fitted into the recess 54 a′ and retained, and then a receiving portion 57 having cylindrical nuts integrally formed thereon is positioned from the outside, and each nut is fitted into the hole.

[0093] Then, a screw that is not shown in the figure is screwed through the screw hole on the bracket 56 and the hole on the bottom wall that is aligned thereto into the nut of the receiving portion 57, so that the bracket 56 and the receiving portion 57 are secured.

[0094] Accordingly, the leg stud 5 having a supporting leg portion 51′ formed of pure wood can be used in the above described embodiment.

[0095] As a matter of course, the connecting structure between the supporting leg portion 51 and the horizontal member 52 is not limited to the embodiment described above.

[0096] When stacking the tables A in accordance with this embodiment, the thickness of the table A is not more than the thickness up to the horizontal member 52, and thus it allows for a compact storage. In this arrangement, it is possible to decrease the thickness of the table, but it is necessary to set the top board A to the length at least twice the length of the leg stud 5.

[0097] Therefore, dephasing the left and right leg studs 5 in the lateral direction so that they are positioned alternately is contemplated to reduce the length of top board A to some extent, but it also has a limit. In addition to it, it is required to increase the width of the top board A.

[0098] Accordingly, a table T4 in accordance with the fourth embodiment shown in FIG. 12 and FIG. 13 has a construction in which the leg studs 5 are folded one on another.

[0099] In this case, only the horizontal member 52 of one of the leg studs 5 is inclined so that the sides to which the supporting leg portions 51 are connected come closer to the top board A when being folded. Therefore, the supporting leg portions 51 are disposed closer to the top board A with respect to the center portion 52 a of the horizontal member 52 when being folded.

[0100] Then, the supporting leg portions 51 of the opposite leg stud (5′ for the convenience of explanation) are disposed so as to be overlaid thereon.

[0101] In this arrangement, the length of the top board A can be reduced as much as possible as shown in the figure, and the width can be determined corresponding to the width of the leg stud 5, thereby realizing further size reduction.

[0102] In this embodiment, the supporting leg portions 51 are formed in plate shape but not in column shape, and the dimensions thereof are determined so that the height of the overlapped supporting leg portions 51 of the opposed separate leg studs 5 does not exceed the height of the center portion 52 a of the horizontal member 52.

[0103] Here, in the tables T3, T4 according to the third and fourth embodiment, the same lock device 1 that is shown in FIG. 17 through FIG. 20 is used.

[0104] The lock device 1 of FIG. 17 through FIG. 19 is the same as the lock device 1 of the tables T2 in the second embodiment, and the lock device 1 of FIG. 20 is different from the lock device 1 of the tables T1 and T2 in the first and the second embodiment in that the fold stopper 23 is not provided, and other constructions are the same.

[0105] In other words, the lock device 1 comprises a supporting bracket 2 including the lock lever 4 rotatably attached thereto with the second pin P2, and the cam bracket 3 to be rotatably attached to the supporting bracket 2 with the first pin P1 in combination.

[0106] The side plate 2 a of the supporting bracket 2 is formed with a recess at the lower edge thereof, which serves as the lock pin stopper 22, and the fold stopper 23 is not formed as described above. Since other constructions are the same as the lock device of the preceding embodiments, the same parts are designated by the same reference numerals and are not described again.

[0107]FIG. 17 shows a state in which the leg stud is deployed, which corresponds to FIG. 6 illustrating the first embodiment.

[0108]FIG. 19 shows a state in which the leg stud is folded, which corresponds to FIG. 4 illustrating the first embodiment.

[0109]FIG. 18 shows a state in which the leg stud is in the course of moving from the folded position to the deployed position.

[0110]FIG. 20A shows a locked state when the leg stud is deployed, FIG. 20B is an explanatory drawing showing a locked state with the leg stud folded, which correspond to FIGS. 7A and 7B illustrating the first embodiment respectively.

[0111] Since the fold stopper 23 is not provided on the supporting bracket 2, the leg stud 5 does not come into contact with the supporting bracket 2 when being folded.

[0112] Other constructions are the same.

[0113] In this embodiment, since the lock device 1 comprises the supporting bracket 2 including the lock lever 4 rotatably attached thereto and the cam bracket 3, it can be mounted freely irrespective of the types or configurations of the leg stud 5.

[0114] In other words, while the horizontal member 52 of the leg stud 5 was inclined at both ends in the preceding embodiment, it may be any arbitrary configurations such as a construction in which the horizontal member 52 is bent at a right angle or a construction in which the horizontal member 52 is bent with a shoulder.

[0115] The spring 8 may be fitted on the second pin P2, and engaged with the lock lever 4 at one end and with the bottom of the channel of the supporting bracket 2 at the other end, so as to urge the lock lever 4 in the locking direction.

[0116] The supporting bracket 2 may be formed with a side as a fold stopper that comes into contact with the center portion 52 a of the horizontal member 52 when being folded.

[0117] Material of the top board A or of the leg stud 5 may be metal, wood, and resin. What is essential is that the supporting bracket 2 or the cam bracket 3 can be secured. The configuration is not limited to pipe, and may be pure material, round material, or square material.

[0118] The target object to which the lock device 1 is attached is not limited to the table, but may be a desk, a chair, or other furniture or structures as far as the leg stud can be folded and deployed.

[0119] The dimensions of the supporting bracket or the cam bracket are arbitrary, and especially the length along the axis of rotation may be very long. Though a single lock device is provided for each leg stud, it is also possible to provide a plurality of lock devices in the center portion of a single horizontal member.

[0120] The deployment lock receiving portion 32, the fold lock receiving portion 35 and the intermediate cam surface on the cam bracket 3 are not limited to the examples shown in the figures, but the cam surface may be provided in a plurality of positions separately.

[0121] Though the example in which the cam bracket 3 includes a pair of locking cam strips 30 is shown, it is also possible to provide in a single position.

[0122]FIG. 22 to FIG. 24 show a fifth embodiment of this invention.

[0123] In this embodiment, a horizontal member 52 provided of a stand stopper 80 which projects toward a top board.

[0124] The stand stopper 80 is box-shape or block-shape, and integrally attached to the center portion 52 a of the horizontal member 52.

[0125] In this case, the stand stopper 80 comprises a rear plate portion 81, a top plate portion 82, and the left and right side plate portions 83.

[0126] The end of the rear plate portion 81 is welded to the horizontal member 52, and the end of the left and right side plate portions 83 are welded to the projected portion 36′, which is prolonged from the fold receiving surface 36 of the cam bracket 3 and projected from the horizontal member 52.

[0127] The basal plate portion 20 of the supporting bracket 2 is set up widely, so as to be able to come into contact with the top of the plate portion 82 of the stand stopper 80 when the leg stud 5 is deployed.

[0128] The stand stopper 80 is not limited to the configuration shown in the figures, and may be any arbitrary configurations to have enough intency.

[0129] When the leg stud 5 is deployed, the deployment stopper 21 contacts with the projected portion 36′ and constrains the fold receiving surface 36.

[0130] Furthermore, the stand stopper 80 contacts with the basal plate portion 20 and constrains the supporting bracket 2.

[0131] And the space between the horizontal member 52 and the supporting bracket 2 is filled up with the stand stopper 80.

[0132] Accordingly, the leg stud 5, it is deployed and stood up, can be kept strong and stable in the above described embodiment.

[0133] In addition, when the leg stud 5 developed or is folded up, the tip of the cylindrical portion 53 is formed hemispherical, and which is projected to the top board A side (below in FIG. 22) rather than the horizontal member 52.

[0134] Therefore the position of the cylindrical portion 53 (the projected position from the horizontal member 52) is defined by the rotation locus at the tip of the cylindrical portion 53 as a relative relation with the position of the 1st pin P1 so that there may always be untouched the top board A when the leg stud 5 is moving during developed to be folded up.

[0135] In this embodiment, the stand stopper 80 showed the case where it formed apart from the horizontal member 52, however the stand stopper 80 may be formed in the horizontal member 52 as a part of it.

[0136] In short, it is possible to vary in design without modifying the scope of the invention as a matter of course.

[0137] As is described thus far, in the folding structure in accordance with the present invention, the supporting bracket including a lock lever thereon is secured on the basal plate, a cam bracket is fixed on the leg stud, and both of them are rotatably mounted, so that the leg stud can be rotatably mounted to the basal plate.

[0138] The present invention provides a reliable lock structure of the folding leg stud in which locking state may be released by pressing the lock lever in the standby position toward the basal plate, even when the leg stud is deployed, or folded.

[0139] In addition, the overall structure is simplified and thus the costs may be reduced by providing a stopper that constrains the deployed position and the folded position of the leg stud on the supporting bracket to which the leg stud is rotatably mounted.

[0140] Further, in the folding structure in this invention, by inclining both end of the horizontal member of the leg stud toward the basal plate, the supporting leg portions at both ends of the horizontal member can be disposed in contact with the top board while the horizontal member of the leg stud is positioned away therefrom when being folded via a lock device.

[0141] Consequently, the size of the basal plate of the folding structure such as the top board is not constrained significantly by the leg stud, and thus the basal plate can be downsized. When stacking them one on another, since it can be reduced in thickness as much as possible, it is superior in space saving. 

What is claimed is:
 1. A folding structure comprising: a supporting bracket fixed on the basal plate such as a top board or a seat board, and provided with a leg stud rotatably mounted at one end thereon; a lock lever rotatably supported at the other end of the supporting bracket, provided with a locking portion formed of a lock pin at one end and an operating strip at the other end, and urged in the locking direction; and a locking cam strip fixed to the leg stud so that the locking portion is always in contact therewith; the locking cam strip further comprising: a fold lock receiving portion formed in the position where the locking portion engages in a standby position in which the operating strip is disposed between the folded leg stud and the basal plate when the leg stud is folded, and a deployment lock receiving portion provided in the position away from the fold lock receiving portion by the angle corresponding to the angle between the deployed position and the folded position of the leg stud about a fulcrum at which the leg stud is rotatably attached, and formed in the position where the locking portion engages when the leg stud is deployed with the operating strip taking almost the same position as the standby position which is taken when the leg stud is being folded; wherein the respective locking state is released by pressing the lock lever in the standby position toward the basal plate when the leg stud is in the deployed position and in the folded position.
 2. A folding structure as set forth in claim 1, wherein the locking cam strip is formed on a side plate of the cam bracket secured to the leg stud, and wherein the cam strip comprises a passage section to which the locking portion comes into the space between the locking cam strip and the leg stud when folding the leg stud, and a fold lock receiving portion recessed in the passage section for engaging the locking portion.
 3. A folding structure as set forth in claim 1 or 2, wherein the supporting bracket is formed at the end thereof with a recessed locking portion stopper that comes in alignment with the fold lock receiving portion displaced when the leg stud is folded for rotatably supporting the locking portion.
 4. A folding structure as set forth in claim 1, 2 or 3, wherein the supporting bracket is formed with a deployment stopper at one end thereof for determining the deployed position of the leg stud by being brought into contact with the leg stud when the leg stud is deployed.
 5. A folding structure as set forth in claim 1, 2, 3 or 4, wherein the supporting bracket is formed with a fold stopper at the lowest edge thereof for determining the folded position of the leg stud by being brought into contact with the leg stud when the leg stud is folded.
 6. A folding structure as set forth in claim 1, wherein the pair of leg studs provided on both end portions of the folding structure comprises a pair of supporting leg portions and a horizontal member for connecting the supporting leg portions, and wherein each horizontal member is formed in such a manner that the sides to which the supporting portions are connected move closer to the basal plate when the leg stud is folded, so that the supporting leg portions are disposed in the positions closer to the basal plate with respect to the horizontal member when the let stud is folded.
 7. A folding structure as set forth in claim 1, wherein the pair of leg studs provided in the both end portions of the folding structure each comprises a pair of supporting leg portions and the horizontal member for connecting the supporting leg portions, and are adapted to be folded in such a manner that the supporting leg portions of the opposed leg studs are placed one on another, and wherein only one of the horizontal members is formed in such a manner that the sides to which the supporting leg portions are connected move closer to the basal plate when the leg stud is folded so that the supporting leg portions are disposed closer to the basal plate with respect to the horizontal member when the leg stud is folded, and wherein the supporting leg portions on the side of the other horizontal member are disposed so as to be superimposed on the supporting leg portions on one side.
 8. A folding structure as set forth in claim 6 or 7, wherein the horizontal member is obliquely inclined at both ends thereof and the supporting leg portions are secured at the ends thereof.
 9. A folding structure as set forth in claim 1, wherein the pair of leg studs provided on both end portions of the folding structure comprises a pair of supporting leg portions and a horizontal member for connecting the supporting leg portions, and wherein the horizontal member is formed with a stand stopper which is brought into contact with a basal plate portion of the supporting bracket fixed on the basal plate when the let stud is deployed. 